Microscope condenser series

ABSTRACT

A related series of interchangeable phase condensers of substantially the same focal length having compatible parfocality, but having different working distances. The series of condensers being of such a design that ordinary correction of the image plane is within at least two wave lengths of light; the condensers being well corrected for field aberration including coma, and pupil aberration including coma; said condensers having their respective pupil positions substantially external to the glass thereof. By &#39;&#39;&#39;&#39;substantially external&#39;&#39;&#39;&#39; is meant all of the condensers have their annulii, aperture stops and focal plane positions substantially coincident.

I United State +1 1 7 gm 3,790,254

I o Rybickr et al. 7 4 7 [451 Feb. 5, 1974 [54] MICROSCOPE CONDENSER SERIES 3,421,808 H1969 Gottlieb... 350/87 1 Inventors: Edward B. y Buffalo; Mum 3,679,287 7/1972 Takahashl et a] 350/39 X H. Sussman, Amherst' Robert B.

Pnmary Exammer-John K. Corbm g s wnhamsvme of Attorney, Agent, or Firm--Alan H. Spencer; William l C. Nealon; Bernard L. Sweeney [73] Assignee: American Optical Corporation,

Southbridge, Mass. 57 ABSTRACT [22] Filed; Se t. 7, 1972 A related series of interchangeable phase condensers of substantially the same focal length having compati- [211 App]? 287,133 ble parfocality, but having different working distances. The series of condensers being of such a design that [52] US. Cl 350/183, 350/87, 350/220, ordinary correction of the image plane is within at 350/229 least two wave lengths of light; the condensers being 511 nt. CI. ;ggp 21/0s ll r q g, 9! fi w b l k iii W [5 8 fiififsearea 350/220, 229, 38, 39, 87, and pupil aberration including coma; siidYondensers 3 56/T75 M L, 183 having their respective pupil positions substantially/extemal to the glass thereof. By substantially external is meant all of the condensers have their annulii, aper- [56] References Cited ture stops and focal plane positions substantially coin- UNITED STATES PATENTS 3,l37,76l 6/1964 Conradi et a]. 350/220 X 10 Claims, 3 Drawing Figures PUP/L PLANE PAIENTEDFEB 3.190.254

SHEEI10F3 PUP/L PLHNE PATENIEU FEB 51974 3.790.254

SHEU 2 0F 3 DZ R2 PATENTEHFEB 51914 3.790.254

SHEEI 30F 3 PUP/L PLA E FIG. 3

1 MICROSCOPE CONDENSER SERIES BACKGROUND OF THE INVENTION It is common with certain types of microscopes to have a plurality of more or less interchangeable condensers. However, such a change in condensers with a given microscope has required or necessitated the change of phase annuli. According to the present invention, a series of related condensers is provided, the equivalent focal lengths of which, allow the same phase annuli to be used with all condensers.

In addition, significant aspects of this invention include that the condensers are well corrected for both field and pupil aberrations and of particular significance is that the pupil positions of each condenser in the series is external to the glass in a given said condenser.

The correction for both field and pupil aberrations is significant in that the condensers perform well for both phase and non-phase applications. For the non-phase application, only field correction is necessary. With the phase application, both field and pupil correction are necessary with the pupil correction being especially important. In the prior art special condensers were necessary on a given microscope for phase applications.

As mentioned above, the pupil positions of the various condensers in the series are external to the glass. This external pupil position is significant since it has been found desirable to place phase annuli as near as possible to the pupil position. This is accomplished with superior facility with an external pupil. In the prior art, the annuli was further removed from the focal plane, and significantly inferior phase performance was encountered.

OBJECTS OF THE INVENTION Accordingly, it is among the objects of this invention to provide a series or group of cooperating microscope condensers usable with a single microscope.-

Another object of the invention is to provide a series.

DRAWINGS FIG. 1 is an optical diagram of one of a series of condensers according to this invention represented as an optical diagram of a condenser having an NA of 1.30.

FIG. 2 is an optical diagram of one of a series of condensers according to this invention represented as an optical diagram of a condenser having a long working distance.

FIG. 3 is an optical diagram of one of a series of condensers according to this invention represented as an optical diagram of a condenser having an NA of 0.90.

DESCRIPTION According to this invention, there is provided, according to a preferred embodiment, a series of three interchangeable cooperatively designed microscope condensers. The exemplary condenser series includes one having an NA of 1.30, one having an NA of 0.90, and a long working distance condenser. In the tables given below, numerical values for a successful variation of the condensers just mentioned are given.

THE 1.30 NA CONDENSER This condenser as shown in FIG. 1 is a microscope sub-stage condenser, and in particular, an infinity corrected, achromatic, oil immersion condenser with a numerical aperture of substantially 1.30. It is corrected for field aberrations including coma. It is corrected for pupil aberrations, especially coma. Its pupil position is external to the glass and its focal length and parfocality are compatible with other condensers in the exemplary series herein described.

Referring to FIG. 1, where Roman numerals I, II, and Ill designate the three optically aligned components of said invention. Component I is a doublet composed of a plane parallel plate cemented to a hemispherical lens. Component II is a meniscus positive lens, followed by component III, a convex positive triplet.-

The lens parameters are given with the following notations:

Axial thicknesses are designated T1 to T6,

Axial air separations are designated 81 to S3,

Lens radii are designated R1 to R9, where the minus sign applies to surfaces whose center of curvature lies on the side of their vertices toward the pupil plane,

Refractive indices are designated NDl to ND6, and

Abbe numbers are designated v1 to v6.

Numerically stated, the constructional data for one successful form of the invention is given in the chart below:

The foregoing parameters of radius, thickness, and spacings are functions of the equivalent focal length F of the condenser. In this preferred embodiment, the value of F, as an example is 9.67521 millimeters. In this focal length, the absolute value of the foregoing data is as follows:

TABLE II Radius Thicknes Space Refractive Abbe R T S Index Number ND v Sl=0. l2 l 8F Rl=4.3652F Tl=0.7586F NDl=l.696800vl=55.41

T2==0. l 550F ND2=l .805 l 82v2=25.43 R3=l l .948F

THE LONG WORKING DISTANCE CONDENSER As a second condenser in the preferred, yet exemplary series of condensers herein disclosed, there is a long working distance condenser. It is a microscope sub-stage condenser which is infinity corrected, achromatic, and dry. It is corrected for field aberrations, including coma, pupil aberrations, and has a working distance of substantially 5.5 millimeters in air. lts numerical aperture is substantially 0.65 and its pupil position, parfocality, and focal length are compatible with other condensers in the series herein disclosed.

FIG. 2 is an optical diagram of the present invention, wherein numerals I, II, III, and IV designate the four optically aligned components of said invention. Components I, II, and III are meniscus positive lenses, while component IV is a convex negative triplet.

The lens parameters are given with the following notations:

Axial thicknesses are designated T1 to T6,

Axial air separations are designated 81 to S4, where the minus sign indicates the two surfaces are shown in the opposite order in FIG. 2,

Lens radii are designated R1 to R10, where the minus sign applies to surfaces whose center of curvature lies on the side of their vertices toward the pupil plane,

Refractive indices are designated NDl to ND6, and

Abbe numbers are designated v] to 1/6.

Numerically stated, the constructional data for one successful form of the invention is given in the chart below.

The foregoing parameters of radius, thickness, and spacings are functions of the equivalent focal length F of the condenser. In this preferred embodiment, the value of F, as an example, is 9.67528 millimeters. In this focal length, the absolute value of the foregoing data is as follows:

THE 0.90 NA CONDENSER The condenser as shown in FIG. 3 is a microscope sub-stage condenser, and in particular, an infinity corrected, achromatic, dry condenser, with a numerical aperture of substantially 0.90. It is corrected for field aberrations, including coma. It is also corrected for pupil aberrations, especially coma. lts pupil position is external to the glass and its focal length and parfocality are compatible with other condensers in the exemplary series herein described.

FIG. 3 is an optical diagram of the present invention, wherein numerals I, II, and Ill designate the three optically aligned components of said invention. Component I is a meniscus positive lens, as is component ll. Component III is a convex positive triplet.

The lens parameters are given with the following notations:

Axial thicknesses are designated T1 to T5,

Axial air separations are designated S1 to S3,

Lens radii are designated R1 to R8, where the minus sign applies to surfaces whose center of curvature lies on the side of their vertices toward the pupil plane,

Refractive indices are designated NDl to NDS, and

Abbe numbers are designated 1 1 to 1/5.

Numerically stated, the constructional data for one successful form of the invention is given in the chart below:

TABLE V Radius Thickness Space Refractive Abbe R T S Index Number ND v Sl=l.300 Rl=39.784

Tl=8.440 NDl=l.69680vl=55.39 R2=l0.826

T2=2.500 ND2=l.805l8v2=25.43 R3=28.936

I T3=l.600 ND3=I.69680| 3=55.39 R4=98.903

S2=0.ll00

R5=ll.042

T4=5.650 ND4=l.69680v4=55.39

T5=7.5 l2 ND5==l .56384v5=60.82

The foregoing parameters of radius, thickness, and spacings are functions of the equivalent focal length F of the condenser. In this preferred embodiment, the value of F, as-an example is 9.67529 millimeters. In this focal length, the absolute value of the foregoing data is as follows:

In the foregoing tables, negative signs represent concave radii going from left to right.

In the whole description, we have emphasized that the annuli, aperture stops and pupil positions are substantially coincident. As will be recognized by those skilled in the art, this means that when the condensers are utilized in a contrast enhancing system, the annuli identically placed below and exterior to any of the aforementioned condensers are imaged so coincident that common (meaning same") retardation plates or spatial filtering devices may be used.

It should be understood by those skilled in the art that the lens data is accurate within about t 3 percent in the second decimal place.

Having thus described the invention in detail and with sufficient particularity to enable those skilled in the art to practice it, what is desired to have protected by Letters Patent is set forth in the following claims.

What is claimed is:

l. A related series of interchangeable phase condensers of substantially the same focal length having compatible parfocality, but having different working distances, the series of condensers being of such a design that ordinary correction of the image plane is within at least two wave lengths of light; the condensers being well corrected for field aberration including coma, and pupil aberration including coma; said condensers having their respective pupil positions external to the glass thereof in a light path through a given condenser in the series and each condenser comprising at least three lens components, the last of said lens components being a double convex triplet and the second of said lens components being a meniscus positive lens.

2. A microscope condenser in a series according to claim 1 having a numerical aperture of 1.30 and composed of the following components:

a first component I comprised of a doublet composed of a plane parallel plate cemented to a hemispherical lens;

a second component ll comprised of a meniscus positive lens; and

a third component Ill, composed of a convex positive triplet.

3. The microscope condenser of claim 2 in which the parameters of lens radii (R), thicknesses (T), and spacings (S') are expressed in millimeters and a negative sign indicates lens radii on centers of curvature on the object side of the lens 4. The microscope condenser of claim 3 in which 5. A microscope condenser in a series according to claim 1 having a working distance of substantially 5.5 millimeters in air, and a numerical aperture of substantially 0.65 and composed of the following components:

a first, second, and third component I, ll, and Ill,

each comprised of a meniscus positive lens, and

a fourth component lV, comprised of a convex negative triplet.

6. The microscope condenser of claim 5 in which the parameters of lens radii (R), thicknesses (T) and spacings (S) are expressed in millimeters and a negative sign indicates lens radii on centers of curvature on the object side of the lens sign indicates lens radii on centers of curvature on the object side of the lens NDS-l .56384v 540.32

10. The microscope condenser of claim 9 in which 

1. A related series of interchangeable phase condensers of substantially the same focal length having compatible parfocality, but having different working distances, the series of condensers being of such a design that ordinary correction of the image plane is within at least two wave lengths of light; the condensers being well corrected for field abErration including coma, and pupil aberration including coma; said condensers having their respective pupil positions external to the glass thereof in a light path through a given condenser in the series and each condenser comprising at least three lens components, the last of said lens components being a double convex triplet and the second of said lens components being a meniscus positive lens.
 2. A microscope condenser in a series according to claim 1 having a numerical aperture of 1.30 and composed of the following components: a first component I comprised of a doublet composed of a plane parallel plate cemented to a hemispherical lens; a second component II comprised of a meniscus positive lens; and a third component III, composed of a convex positive triplet.
 3. The microscope condenser of claim 2 in which the parameters of lens radii (R), thicknesses (T), and spacings (S) are expressed in millimeters and a negative sign indicates lens radii on centers of curvature on the object side of the lens TABLE II Radius Thickness Space Refractive Abbe R T S Index Number ND Nu S1 0.1218F R1 4.3652F T1 0.7586F ND1 1.696800 Nu 1 55.41 R2 2.2949F T2 0.1550F ND2 1.805182 Nu 2 25.43 R3 11.948F T3 0.2770F ND3 1.696800 Nu 3 55.41 R4 12.679F S2 0.01137F R5 1.5317F T4 0.4331F ND4 1.696800 Nu 4 55.41 R6 3.0139F S3 0.03101F R7 0.75399FT5 0.8940F ND5 1.617650 Nu 5 44.14 R8 PLANO T6 0.1550F ND6 1.784701 Nu 6 26.08 R9 PLANO
 4. The microscope condenser of claim 3 in which F 9.67521.
 5. A microscope condenser in a series according to claim 1 having a working distance of substantially 5.5 millimeters in air, and a numerical aperture of substantially 0.65 and composed of the following components: a first, second, and third component I, II, and III, each comprised of a meniscus positive lens, and a fourth component IV, comprised of a convex negative triplet.
 6. The microscope condenser of claim 5 in which the parameters of lens radii (R), thicknesses (T) and spacings (S) are expressed in millimeters and a negative sign indicates lens radii on centers of curvature on the object side of the lens TABLE IV Radius Thickness Space Refractive Abbe R T S Index Number ND Nu S1 -0.01333 R1 10.336F T1 0.1550 ND1 1.96051 Nu 1 34.90 R2 1.0336F T2 0.6873 ND2 1.60310 Nu 2 65.34 R3 -1.1797F T3 0.1550 ND3 1.96051 Nu 3 34.90 R4 -4.1166F S2 0.005167 R5 -32.798F T4 0.4847 ND4 1.69680 Nu 4 55.39 R6 -1.9954F S3 0.005167 R7 1.5817F T5 0.6718 ND5 1.69680 Nu 5 55.39 R8 2.8103F S4 0.005167 R9 0.9984F T6 0.5400 ND6 1.69680 Nu 6 55.39 R10 5.1678F
 7. The microscope condenser of claim 6 in which F 9.67528.
 8. A microscope condenser in a series according to claim 1 having a numerical aperture of 0.90 and composed of the following components: a first and second component I, and II, comprised of a meniscus positive lens, and a third component III comprised of a convex positive triplet.
 9. The microscope condenser of claim 8 in which the parameters of lens radii (R), thicknessEs (T), and spacings (S) are expressed in millimeters and a negative sign indicates lens radii on centers of curvature on the object side of the lens TABLE VI Radius Thickness Space Refractive Abbe R T S Index Number ND Nu S1 0.1344F R1 4.1119F T1 0.8723F ND1 1.69680 Nu 1 55.39 R2 -1.1189F T2 0.2584F ND2 1.80518 Nu 2 25.43 R3 -2.9907F T3 0.1654F ND3 1.69680 Nu 3 55.39 R4 -10.222F S 0.01137F R5 1.1413F T4 0.5840F ND4 1.69680 Nu 4 55.39 R6 2.8435F S3 0.0310F R7 0.77569F T5 0.7764F ND5 1.56384 Nu 5 60.32 R8 5.1726F
 10. The microscope condenser of claim 9 in which F 9.67529. 